Change PHINode::hasConstantValue to have a DominatorTree argument

instead of a bool argument, and to do the dominator check itself.
This makes it eaiser to use when DominatorTree information is
available.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80920 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 21 insertions, 28 deletions

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 56bc816c..36c90f5 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -769,7 +769,7 @@ static bool isSafeReplacement(PHINode* p, Instruction* inst) {
 }
 
 Value* GVN::CollapsePhi(PHINode* p) {
-  Value* constVal = p->hasConstantValue();
+  Value* constVal = p->hasConstantValue(DT);
   if (!constVal) return 0;
   
   Instruction* inst = dyn_cast<Instruction>(constVal);
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index c3d6194..c165e04 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -429,13 +429,10 @@ BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
     PN->addIncoming(InVal, NewBB);
     
     // Check to see if we can eliminate this phi node.
-    if (Value *V = PN->hasConstantValue(DT != 0)) {
-      Instruction *I = dyn_cast<Instruction>(V);
-      if (!I || DT == 0 || DT->dominates(I, PN)) {
-        PN->replaceAllUsesWith(V);
-        if (AA) AA->deleteValue(PN);
-        PN->eraseFromParent();
-      }
+    if (Value *V = PN->hasConstantValue(DT)) {
+      PN->replaceAllUsesWith(V);
+      if (AA) AA->deleteValue(PN);
+      PN->eraseFromParent();
     }
   }
   
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index c981a01..56e5a46 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -255,7 +255,7 @@ ReprocessLoop:
   PHINode *PN;
   for (BasicBlock::iterator I = L->getHeader()->begin();
        (PN = dyn_cast<PHINode>(I++)); )
-    if (Value *V = PN->hasConstantValue()) {
+    if (Value *V = PN->hasConstantValue(DT)) {
       if (AA) AA->deleteValue(PN);
       PN->replaceAllUsesWith(V);
       PN->eraseFromParent();
@@ -417,14 +417,13 @@ static PHINode *FindPHIToPartitionLoops(Loop *L, DominatorTree *DT,
   for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ) {
     PHINode *PN = cast<PHINode>(I);
     ++I;
-    if (Value *V = PN->hasConstantValue())
-      if (!isa<Instruction>(V) || DT->dominates(cast<Instruction>(V), PN)) {
-        // This is a degenerate PHI already, don't modify it!
-        PN->replaceAllUsesWith(V);
-        if (AA) AA->deleteValue(PN);
-        PN->eraseFromParent();
-        continue;
-      }
+    if (Value *V = PN->hasConstantValue(DT)) {
+      // This is a degenerate PHI already, don't modify it!
+      PN->replaceAllUsesWith(V);
+      if (AA) AA->deleteValue(PN);
+      PN->eraseFromParent();
+      continue;
+    }
 
     // Scan this PHI node looking for a use of the PHI node by itself.
     for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index 6a56a8d..8274e5a 100644
--- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -494,17 +494,14 @@ void PromoteMem2Reg::run() {
       PHINode *PN = I->second;
       
       // If this PHI node merges one value and/or undefs, get the value.
-      if (Value *V = PN->hasConstantValue(true)) {
-        if (!isa<Instruction>(V) ||
-            properlyDominates(cast<Instruction>(V), PN)) {
-          if (AST && isa<PointerType>(PN->getType()))
-            AST->deleteValue(PN);
-          PN->replaceAllUsesWith(V);
-          PN->eraseFromParent();
-          NewPhiNodes.erase(I++);
-          EliminatedAPHI = true;
-          continue;
-        }
+      if (Value *V = PN->hasConstantValue(&DT)) {
+        if (AST && isa<PointerType>(PN->getType()))
+          AST->deleteValue(PN);
+        PN->replaceAllUsesWith(V);
+        PN->eraseFromParent();
+        NewPhiNodes.erase(I++);
+        EliminatedAPHI = true;
+        continue;
       }
       ++I;
     }